Ligation involves applying a band or ligature around a portion of tissue, thereby cutting off blood or fluid flow and causing the tissue to necrose and separate from adjacent healthy tissue. It is widely used to treat a number of medical conditions, including, but not limited to, hemorrhoids, polyps, ballooning varices, and other types of lesions, including those that are cancerous. Various types of instrumentation have been developed that are capable of deploying one or more preloaded ligating bands with the emphasis being on minimally-invasive devices that can be introduced through a natural body opening. The two primary types of ligating band dispensers are those designed to fit over, or work within an endoscope for treating sites that cannot be viewed directly, and simpler, stand-alone devices designed for situations where use of a standard endoscope is not necessary or required. Typically, both types are used with a suction or vacuum means to draw the tissue into the distal tip, whereby the band is deployed over the base of the diseased tissue to cut off blood flow.
In certain instances, it may become necessary or desirable to deploy more than a single ligating band during a procedure. To prevent having to withdraw the instrument from the patient, reload, and reintroduce it for treating additional lesions, devices have been developed capable of sequentially delivering multiple bands that are preloaded, thus shortening the procedure time and improving patient comfort. Typically, multiple band ligating devices include designs with increased mechanical complexity over devices that dispense a single band. One solution to dispensing multiple bands includes individually tethering or otherwise securing the bands to the dispenser and then releasing them sequentially as needed, often by use of one or more strings or wires extending to the proximal end. Various other methods have included using cooperating inner and outer members that slide the individual bands by pushing or pulling them from the tip of the inner or outer member, the bands being preloaded onto the inner or outer member prior to deployment. Unfortunately, each of these methods has been primarily designed for operation with an endoscope and thus, are not ideally suited for incorporation into a separate hand-operated device, which is a highly desirable feature for stand-alone dispensers, such as those used to band hemorrhoids.
Hand-operated ligation band devices are typically less costly to use than types that are used with an endoscope and are especially well-suited when direct access is less of a problem, such as when ligating hemorrhoids. Although a proctoscope or sigmoidoscope may be used for hemorrhoid ligation, these procedures may be conducted ‘blind’ or ‘semi-blind’ using the dentate line inside the rectum as a guide for correct positioning of the device. With most hemorrhoids occurring in this vicinity, some physicians do not feel the need to perform the procedure with visual assistance, while others prefer to increase accuracy of placement by using a simple anoscope (a simple funnel-like device) to help position the ligating band dispenser. Thus, it is especially desirable to make these devices operable with a single hand so that the physician can use the other hand to manipulate the anoscope. There is some disagreement with these single band, single-handed ligating band dispensers to the number of bands that can be safely applied per session with most reporting that either two or three should be the maximum attempted. This is due in part to the need for reintroducing the device following each reloading procedure.
An ideal multiple-band dispenser for hemorrhoid ligation should include a suction means to draw the tissue into the tip, it should be operable using a single hand, and it should be capable of delivering the bands precisely and accurately from the tip of the device using a minimal amount of manipulation of the proximal actuating mechanism. A secondary goal is for delivery to be accomplished in a smooth manner, such that there is minimal or no movement of the distal portion of the apparatus during deployment.